Embodiments herein include thin-film transistors (TFTs) including channel layer stacks with layers having differing mobilities. The TFTs disclosed herein transport higher total current through both the low mobility and the high mobility channel layers due to higher carrier density in high mobility channel layer and/or the high mobility channel layers, which increases the speed of response of the TFTs. The TFTs further include a gate structure disposed over the channel layer stack. The gate structure includes one or more gate electrodes, and thus the TFTs are top-gate (TG), double-gate (DG), or bottom-gate (BG) TFTs. The channel layer stack includes a plurality of layers with differing mobilities. The layers with differing mobilities confer various benefits to the TFT. The high mobility layer increases the speed of response of the TFT.